Your commission validation approvals period is the time between when a conversion takes place and when that conversion locks and is thus deemed valid to be paid out as commission to the affiliates. All transactions will auto-lock once they pass the set time frame.
By default the commission approval time period is 30 days as this is the industry standard time frame. If you wish to make this longer, please contact your Commission Factory account contact to assist with this. It's worth noting that the longer the commission approval timeframe the longer it will be for your affiliates to get paid.